Re: [Xen-devel] [PATCH] ioemu: Clone ioemu with --depth=1

[Jean Guyader <jean.guyader@xxxxxxxxx>]

On 1 November 2011 21:52, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:
> On Tue, 2011-11-01 at 17:32 -0400, Daniel De Graaf wrote:
>> On 11/01/2011 01:33 PM, Jean Guyader wrote:
>> >
>> > Signed-off-by: Jean Guyader <jean.guyader@xxxxxxxxxx>
>> >
>> > diff --git a/tools/Makefile b/tools/Makefile
>> > index 9389e1f..6c1dfe0 100644
>> > --- a/tools/Makefile
>> > +++ b/tools/Makefile
>> > @@ -92,7 +92,7 @@ ioemu-dir-find:
>> >             if [ ! -d ioemu-remote ]; then \
>> >                     rm -rf ioemu-remote ioemu-remote.tmp; \
>> >                     mkdir ioemu-remote.tmp; rmdir ioemu-remote.tmp; \
>> > -                   $(GIT) clone $(CONFIG_QEMU) ioemu-remote.tmp; \
>> > +                   $(GIT) clone --depth=1 $(CONFIG_QEMU) 
>> > ioemu-remote.tmp; \
>> >                     if [ "$(QEMU_TAG)" ]; then                      \
>> >                             cd ioemu-remote.tmp;                    \
>> >                             $(GIT) branch -D dummy >/dev/null 2>&1 ||:; \
>>
>> This will break if QEMU_TAG is pointing to any commit that is more than
>> one commit away from a branch or tag in the source repository.
>
> Good point. We could do e.g. --depth=2000 which takes history back to
> some time in 2007.
>
> On the other hand a full clone takes ~30s and a --depth=2000 takes ~20s
> (both elapsed wallclock times) so it's not clear that there is all that
> much benefit in the context of how long everything actually takes to
> build, especially given the big clone only happens once per build tree.
>

I don't think it's fair to measure things in seconds here since it's very much
depend on the Internet connection people are using. When building tip
of xen-unstable
we are actually downloading 3 times as much data that we actually need
(9.9M instead of 29.11M).

I figured that if we don't need to download everything to build we
shouldn't. I submitted a patch
because I ended up downloading the tree manually to speed thing up,
but if you think my patch isn't
appropriate that is fine.

I think this sort of patch would have a much bigger impact when we are
cloning the Linux
kernel.

Jean

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